[Plugin: WP Super Cache] I am recieving this error w/ my .htaccess

Trailing slash check required.

It looks like your blog has URLs that end with a ‘/’. Unfortunately since you installed this plugin a duplicate content bug has been found where URLs not ending in a ‘/’ end serve the same content as those with the ‘/’ and do not redirect to the proper URL.To fix, you must edit your .htaccess file and add these two rules to the two groups of Super Cache rules:

RewriteCond %{REQUEST_URI} !^.*[^/] %{REQUEST_URI} !^.*//.*$

You can see where the rules go and examine the complete rules by clicking the ‘View mod_rewrite rules’ link below.

WP Super Cache mod rewrite rules were detected in your /home/mercu10/public_html/symboldictionary/.htaccess file.
Click the following link to see the lines added to that file. If you have upgraded the plugin make sure these rules match.

View Mod_Rewrite Rules

# BEGIN WPSuperCache
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
AddDefaultCharset UTF-8
RewriteCond %{REQUEST_URI} !^.*[^/]$
RewriteCond %{REQUEST_URI} !^.*//.*$
RewriteCond %{REQUEST_METHOD} !=POST
RewriteCond %{QUERY_STRING} !.*=.*
RewriteCond %{HTTP:Cookie} !^.*(comment_author_|wordpress|wp-postpass_).*$
RewriteCond %{HTTP:Accept-Encoding} gzip
RewriteCond %{DOCUMENT_ROOT}/wp-content/cache/supercache/%{HTTP_HOST}/$1/index.html.gz -f
RewriteRule ^(.*) /wp-content/cache/supercache/%{HTTP_HOST}/$1/index.html.gz [L]

RewriteCond %{REQUEST_URI} !^.*[^/]$
RewriteCond %{REQUEST_URI} !^.*//.*$
RewriteCond %{REQUEST_METHOD} !=POST
RewriteCond %{QUERY_STRING} !.*=.*
RewriteCond %{HTTP:Cookie} !^.*(comment_author_|wordpress|wp-postpass_).*$
RewriteCond %{DOCUMENT_ROOT}/wp-content/cache/supercache/%{HTTP_HOST}/$1/index.html -f
RewriteRule ^(.*) /wp-content/cache/supercache/%{HTTP_HOST}/$1/index.html [L]
</IfModule>
# END WPSuperCache

Rules must be added to /home/mercu10/public_html/symboldictionary/wp-content/cache/.htaccess too:

# BEGIN supercache
<IfModule mod_mime.c>
AddEncoding gzip .gz
AddType text/html .gz
</IfModule>
<IfModule mod_deflate.c>
SetEnvIfNoCase Request_URI \.gz$ no-gzip
</IfModule>
<IfModule mod_headers.c>
Header set Cache-Control ‘max-age=300, must-revalidate’
</IfModule>
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType text/html A300
</IfModule>
# END supercache

I do have the site in a subdirectory on root. I am not very code literate and I was hoping for some advice here.

Jason